git.sur5r.net Git - cc65/blob - src/cc65/codeinfo.c

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                codeinfo.c                                 */
   4 /*                                                                           */
   5 /*                  Additional information about 6502 code                   */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2001      Ullrich von Bassewitz                                       */
  10 /*               Wacholderweg 14                                             */
  11 /*               D-70597 Stuttgart                                           */
  12 /* EMail:        uz@cc65.org                                                 */
  13 /*                                                                           */
  14 /*                                                                           */
  15 /* This software is provided 'as-is', without any expressed or implied       */
  16 /* warranty.  In no event will the authors be held liable for any damages    */
  17 /* arising from the use of this software.                                    */
  18 /*                                                                           */
  19 /* Permission is granted to anyone to use this software for any purpose,     */
  20 /* including commercial applications, and to alter it and redistribute it    */
  21 /* freely, subject to the following restrictions:                            */
  22 /*                                                                           */
  23 /* 1. The origin of this software must not be misrepresented; you must not   */
  24 /*    claim that you wrote the original software. If you use this software   */
  25 /*    in a product, an acknowledgment in the product documentation would be  */
  26 /*    appreciated but is not required.                                       */
  27 /* 2. Altered source versions must be plainly marked as such, and must not   */
  28 /*    be misrepresented as being the original software.                      */
  29 /* 3. This notice may not be removed or altered from any source              */
  30 /*    distribution.                                                          */
  31 /*                                                                           */
  32 /*****************************************************************************/
  33
  34
  35
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 /* common */
  40 #include "coll.h"
  41
  42 /* cc65 */
  43 #include "codeent.h"
  44 #include "codeseg.h"
  45 #include "datatype.h"
  46 #include "error.h"
  47 #include "symtab.h"
  48 #include "codeinfo.h"
  49
  50
  51
  52 /*****************************************************************************/
  53 /*                                   Data                                    */
  54 /*****************************************************************************/
  55
  56
  57
  58 /* Table listing the function names and code info values for known internally
  59  * used functions. This table should get auto-generated in the future.
  60  */
  61 typedef struct FuncInfo FuncInfo;
  62 struct FuncInfo {
  63     const char*     Name;       /* Function name */
  64     unsigned short  Use;        /* Register usage */
  65     unsigned short  Chg;        /* Changed/destroyed registers */
  66 };
  67
  68 static const FuncInfo FuncInfoTable[] = {
  69     { "addysp",         REG_Y,                REG_NONE                       },
  70     { "aslax1",         REG_AX,               REG_AX | REG_TMP1              },
  71     { "aslax2",         REG_AX,               REG_AX | REG_TMP1              },
  72     { "aslax3",         REG_AX,               REG_AX | REG_TMP1              },
  73     { "aslax4",         REG_AX,               REG_AX | REG_TMP1              },
  74     { "bnega",          REG_A,                REG_AX                         },
  75     { "bnegax",         REG_AX,               REG_AX                         },
  76     { "bnegeax",        REG_EAX,              REG_EAX                        },
  77     { "booleq",         REG_NONE,             REG_AX                         },
  78     { "boolge",         REG_NONE,             REG_AX                         },
  79     { "boolgt",         REG_NONE,             REG_AX                         },
  80     { "boolle",         REG_NONE,             REG_AX                         },
  81     { "boollt",         REG_NONE,             REG_AX                         },
  82     { "boolne",         REG_NONE,             REG_AX                         },
  83     { "booluge",        REG_NONE,             REG_AX                         },
  84     { "boolugt",        REG_NONE,             REG_AX                         },
  85     { "boolule",        REG_NONE,             REG_AX                         },
  86     { "boolult",        REG_NONE,             REG_AX                         },
  87     { "complax",        REG_AX,               REG_AX                         },
  88     { "decax1",         REG_AX,               REG_AX                         },
  89     { "decax2",         REG_AX,               REG_AX                         },
  90     { "decax3",         REG_AX,               REG_AX                         },
  91     { "decax4",         REG_AX,               REG_AX                         },
  92     { "decax5",         REG_AX,               REG_AX                         },
  93     { "decax6",         REG_AX,               REG_AX                         },
  94     { "decax7",         REG_AX,               REG_AX                         },
  95     { "decax8",         REG_AX,               REG_AX                         },
  96     { "decaxy",         REG_AXY,              REG_AX | REG_TMP1              },
  97     { "decsp1",         REG_NONE,             REG_Y                          },
  98     { "decsp2",         REG_NONE,             REG_A                          },
  99     { "decsp3",         REG_NONE,             REG_A                          },
 100     { "decsp4",         REG_NONE,             REG_A                          },
 101     { "decsp5",         REG_NONE,             REG_A                          },
 102     { "decsp6",         REG_NONE,             REG_A                          },
 103     { "decsp7",         REG_NONE,             REG_A                          },
 104     { "decsp8",         REG_NONE,             REG_A                          },
 105     { "incax1",         REG_AX,               REG_AX                         },
 106     { "incax2",         REG_AX,               REG_AX                         },
 107     { "incsp1",         REG_NONE,             REG_NONE                       },
 108     { "incsp2",         REG_NONE,             REG_Y                          },
 109     { "incsp3",         REG_NONE,             REG_Y                          },
 110     { "incsp4",         REG_NONE,             REG_Y                          },
 111     { "incsp5",         REG_NONE,             REG_Y                          },
 112     { "incsp6",         REG_NONE,             REG_Y                          },
 113     { "incsp7",         REG_NONE,             REG_Y                          },
 114     { "incsp8",         REG_NONE,             REG_Y                          },
 115     { "laddeq",         REG_EAXY | REG_PTR1,  REG_EAXY                       },
 116     { "laddeq1",        REG_Y | REG_PTR1,     REG_EAXY                       },
 117     { "laddeqa",        REG_AY | REG_PTR1,    REG_EAXY                       },
 118     { "ldaidx",         REG_AXY,              REG_AX | REG_PTR1              },
 119     { "ldauidx",        REG_AXY,              REG_AX | REG_PTR1              },
 120     { "ldax0sp",        REG_Y,                REG_AX                         },
 121     { "ldaxi",          REG_AX,               REG_AXY | REG_PTR1             },
 122     { "ldaxidx",        REG_AXY,              REG_AX | REG_PTR1              },
 123     { "ldaxysp",        REG_Y,                REG_AX                         },
 124     { "leaasp",         REG_A,                REG_AX                         },
 125     { "negax",          REG_AX,               REG_AX                         },
 126     { "pusha",          REG_A,                REG_Y                          },
 127     { "pusha0",         REG_A,                REG_XY                         },
 128     { "pushax",         REG_AX,               REG_Y                          },
 129     { "pusheax",        REG_EAX,              REG_Y                          },
 130     { "pushw0sp",       REG_NONE,             REG_AXY                        },
 131     { "pushwysp",       REG_Y,                REG_AXY                        },
 132     { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
 133     { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
 134     { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
 135     { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
 136     { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
 137     { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
 138     { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
 139     { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
 140     { "shreax1",        REG_EAX,              REG_AX | REG_TMP1              },
 141     { "shreax2",        REG_EAX,              REG_AX | REG_TMP1              },
 142     { "shreax3",        REG_EAX,              REG_AX | REG_TMP1              },
 143     { "shreax4",        REG_EAX,              REG_AX | REG_TMP1              },
 144     { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
 145     { "stax0sp",        REG_AX,               REG_Y                          },
 146     { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
 147     { "tosdiva0",       REG_AX,               REG_ALL                        },
 148     { "tosdivax",       REG_AX,               REG_ALL                        },
 149     { "tosdiveax",      REG_EAX,              REG_ALL                        },
 150     { "tosmula0",       REG_AX,               REG_ALL                        },
 151     { "tosmulax",       REG_AX,               REG_ALL                        },
 152     { "tosmuleax",      REG_EAX,              REG_ALL                        },
 153     { "tosshreax",      REG_EAX,              REG_EAXY | REG_PTR1 | REG_PTR2 },
 154     { "tosumula0",      REG_AX,               REG_ALL                        },
 155     { "tosumulax",      REG_AX,               REG_ALL                        },
 156     { "tosumuleax",     REG_EAX,              REG_ALL                        },
 157 };
 158 #define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
 159
 160 /* Table with names of zero page locations used by the compiler */
 161 typedef struct ZPInfo ZPInfo;
 162 struct ZPInfo {
 163     unsigned char  Len;         /* Length of the following string */
 164     char           Name[11];    /* Name of zero page symbol */
 165     unsigned short RegInfo;     /* Register info for this symbol */
 166 };
 167 static const ZPInfo ZPInfoTable[] = {
 168     {   4,      "ptr1",         REG_PTR1        },
 169     {   4,      "ptr2",         REG_PTR2        },
 170     {   4,      "ptr3",         REG_PTR3        },
 171     {   4,      "ptr4",         REG_PTR4        },
 172     {   7,      "regbank",      REG_BANK        },
 173     {   7,      "regsave",      REG_SAVE        },
 174     {   2,      "sp",           REG_SP          },
 175     {   0,      "sreg",         REG_SREG_LO     },
 176     {   0,      "sreg+1",       REG_SREG_HI     },
 177     {   4,      "tmp1",         REG_TMP1        },
 178     {   4,      "tmp2",         REG_TMP2        },
 179     {   4,      "tmp3",         REG_TMP3        },
 180     {   4,      "tmp4",         REG_TMP4        },
 181 };
 182 #define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
 183
 184
 185 /*****************************************************************************/
 186 /*                                   Code                                    */
 187 /*****************************************************************************/
 188
 189
 190
 191 static int CompareFuncInfo (const void* Key, const void* Info)
 192 /* Compare function for bsearch */
 193 {
 194     return strcmp (Key, ((const FuncInfo*) Info)->Name);
 195 }
 196
 197
 198
 199 void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
 200 /* For the given function, lookup register information and store it into
 201  * the given variables. If the function is unknown, assume it will use and
 202  * load all registers.
 203  */
 204 {
 205     /* If the function name starts with an underline, it is an external
 206      * function. Search for it in the symbol table. If the function does
 207      * not start with an underline, it may be a runtime support function.
 208      * Search for it in the list of builtin functions.
 209      */
 210     if (Name[0] == '_') {
 211
 212         /* Search in the symbol table, skip the leading underscore */
 213         SymEntry* E = FindGlobalSym (Name+1);
 214
 215         /* Did we find it in the top level table? */
 216         if (E && IsTypeFunc (E->Type)) {
 217
 218             /* A function may use the A or A/X registers if it is a fastcall
 219              * function. If it is not a fastcall function but a variadic one,
 220              * it will use the Y register (the parameter size is passed here).
 221              * In all other cases, no registers are used. However, we assume
 222              * that any function will destroy all registers.
 223              */
 224             FuncDesc* D = E->V.F.Func;
 225             if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
 226                 /* Will use registers depending on the last param */
 227                 SymEntry* LastParam = D->SymTab->SymTail;
 228                 if (SizeOf (LastParam->Type) == 1) {
 229                     *Use = REG_A;
 230                 } else {
 231                     *Use = REG_AX;
 232                 }
 233             } else if ((D->Flags & FD_VARIADIC) != 0) {
 234                 *Use = REG_Y;
 235             } else {
 236                 /* Will not use any registers */
 237                 *Use = REG_NONE;
 238             }
 239
 240             /* Will destroy all registers */
 241             *Chg = REG_ALL;
 242
 243             /* Done */
 244             return;
 245         }
 246
 247     } else {
 248
 249         /* Search for the function in the list of builtin functions */
 250         const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
 251                                         sizeof(FuncInfo), CompareFuncInfo);
 252
 253         /* Do we know the function? */
 254         if (Info) {
 255             /* Use the information we have */
 256             *Use = Info->Use;
 257             *Chg = Info->Chg;
 258             return;
 259         }
 260     }
 261
 262     /* Function not found - assume all CPU registers are input, and all
 263      * registers are changed
 264      */
 265     *Use = REG_AXY;
 266     *Chg = REG_ALL;
 267 }
 268
 269
 270
 271 static int CompareZPInfo (const void* Name, const void* Info)
 272 /* Compare function for bsearch */
 273 {
 274     /* Cast the pointers to the correct data type */
 275     const char* N   = (const char*) Name;
 276     const ZPInfo* E = (const ZPInfo*) Info;
 277
 278     /* Do the compare. Be careful because of the length (Info may contain
 279      * more than just the zeropage name).
 280      */
 281     if (E->Len == 0) {
 282         /* Do a full compare */
 283         return strcmp (N, E->Name);
 284     } else {
 285         /* Only compare the first part */
 286         int Res = strncmp (N, E->Name, E->Len);
 287         if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
 288             /* Name is actually longer than Info->Name */
 289             Res = -1;
 290         }
 291         return Res;
 292     }
 293 }
 294
 295
 296
 297 int IsZPName (const char* Name, unsigned short* RegInfo)
 298 /* Return true if the given name is a zero page symbol. If the RegInfo
 299  * pointer is not NULL, it is filled with the register info for the
 300  * zero page location found.
 301  */
 302 {
 303     /* Search for the zp location in the list */
 304     const ZPInfo* Info = bsearch (Name, ZPInfoTable, ZPInfoCount,
 305                                   sizeof(ZPInfo), CompareZPInfo);
 306
 307     /* Did we find it? */
 308     if (Info) {
 309         /* Found, store register info if requested. */
 310         if (RegInfo) {
 311             *RegInfo = Info->RegInfo;
 312         }
 313         return 1;
 314     } else {
 315         /* Not found */
 316         return 0;
 317     }
 318 }
 319
 320
 321
 322 static unsigned GetRegInfo2 (CodeSeg* S,
 323                              CodeEntry* E,
 324                              int Index,
 325                              Collection* Visited,
 326                              unsigned Used,
 327                              unsigned Unused,
 328                              unsigned Wanted)
 329 /* Recursively called subfunction for GetRegInfo. */
 330 {
 331     /* Follow the instruction flow recording register usage. */
 332     while (1) {
 333
 334         unsigned R;
 335
 336         /* Check if we have already visited the current code entry. If so,
 337          * bail out.
 338          */
 339         if (CE_HasMark (E)) {
 340             break;
 341         }
 342
 343         /* Mark this entry as already visited */
 344         CE_SetMark (E);
 345         CollAppend (Visited, E);
 346
 347         /* Evaluate the used registers */
 348         R = E->Use;
 349         if (E->OPC == OP65_RTS ||
 350             ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
 351             /* This instruction will leave the function */
 352             R |= S->ExitRegs;
 353         }
 354         if (R != REG_NONE) {
 355             /* We are not interested in the use of any register that has been
 356              * used before.
 357              */
 358             R &= ~Unused;
 359             /* Remember the remaining registers */
 360             Used |= R;
 361         }
 362
 363         /* Evaluate the changed registers */
 364         if ((R = E->Chg) != REG_NONE) {
 365             /* We are not interested in the use of any register that has been
 366              * used before.
 367              */
 368             R &= ~Used;
 369             /* Remember the remaining registers */
 370             Unused |= R;
 371         }
 372
 373         /* If we know about all registers now, bail out */
 374         if (((Used | Unused) & Wanted) == Wanted) {
 375             break;
 376         }
 377
 378         /* If the instruction is an RTS or RTI, we're done */
 379         if ((E->Info & OF_RET) != 0) {
 380             break;
 381         }
 382
 383         /* If we have an unconditional branch, follow this branch if possible,
 384          * otherwise we're done.
 385          */
 386         if ((E->Info & OF_UBRA) != 0) {
 387
 388             /* Does this jump have a valid target? */
 389             if (E->JumpTo) {
 390
 391                 /* Unconditional jump */
 392                 E     = E->JumpTo->Owner;
 393                 Index = -1;             /* Invalidate */
 394
 395             } else {
 396                 /* Jump outside means we're done */
 397                 break;
 398             }
 399
 400         /* In case of conditional branches, follow the branch if possible and
 401          * follow the normal flow (branch not taken) afterwards. If we cannot
 402          * follow the branch, we're done.
 403          */
 404         } else if ((E->Info & OF_CBRA) != 0) {
 405
 406             if (E->JumpTo) {
 407
 408                 /* Recursively determine register usage at the branch target */
 409                 unsigned U1;
 410                 unsigned U2;
 411
 412                 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);
 413                 if (U1 == REG_AXY) {
 414                     /* All registers used, no need for second call */
 415                     return REG_AXY;
 416                 }
 417                 if (Index < 0) {
 418                     Index = CS_GetEntryIndex (S, E);
 419                 }
 420                 if ((E = CS_GetEntry (S, ++Index)) == 0) {
 421                     Internal ("GetRegInfo2: No next entry!");
 422                 }
 423                 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 424                 return U1 | U2;         /* Used in any of the branches */
 425
 426             } else {
 427                 /* Jump to global symbol */
 428                 break;
 429             }
 430
 431         } else {
 432
 433             /* Just go to the next instruction */
 434             if (Index < 0) {
 435                 Index = CS_GetEntryIndex (S, E);
 436             }
 437             E = CS_GetEntry (S, ++Index);
 438             if (E == 0) {
 439                 /* No next entry */
 440                 Internal ("GetRegInfo2: No next entry!");
 441             }
 442
 443         }
 444
 445     }
 446
 447     /* Return to the caller the complement of all unused registers */
 448     return Used;
 449 }
 450
 451
 452
 453 static unsigned GetRegInfo1 (CodeSeg* S,
 454                              CodeEntry* E,
 455                              int Index,
 456                              Collection* Visited,
 457                              unsigned Used,
 458                              unsigned Unused,
 459                              unsigned Wanted)
 460 /* Recursively called subfunction for GetRegInfo. */
 461 {
 462     /* Remember the current count of the line collection */
 463     unsigned Count = CollCount (Visited);
 464
 465     /* Call the worker routine */
 466     unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 467
 468     /* Restore the old count, unmarking all new entries */
 469     unsigned NewCount = CollCount (Visited);
 470     while (NewCount-- > Count) {
 471         CodeEntry* E = CollAt (Visited, NewCount);
 472         CE_ResetMark (E);
 473         CollDelete (Visited, NewCount);
 474     }
 475
 476     /* Return the registers used */
 477     return R;
 478 }
 479
 480
 481
 482 unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
 483 /* Determine register usage information for the instructions starting at the
 484  * given index.
 485  */
 486 {
 487     CodeEntry*      E;
 488     Collection      Visited;    /* Visited entries */
 489     unsigned        R;
 490
 491     /* Get the code entry for the given index */
 492     if (Index >= CS_GetEntryCount (S)) {
 493         /* There is no such code entry */
 494         return REG_NONE;
 495     }
 496     E = CS_GetEntry (S, Index);
 497
 498     /* Initialize the data structure used to collection information */
 499     InitCollection (&Visited);
 500
 501     /* Call the recursive subfunction */
 502     R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);
 503
 504     /* Delete the line collection */
 505     DoneCollection (&Visited);
 506
 507     /* Return the registers used */
 508     return R;
 509 }
 510
 511
 512
 513 int RegAUsed (struct CodeSeg* S, unsigned Index)
 514 /* Check if the value in A is used. */
 515 {
 516     return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
 517 }
 518
 519
 520
 521 int RegXUsed (struct CodeSeg* S, unsigned Index)
 522 /* Check if the value in X is used. */
 523 {
 524     return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
 525 }
 526
 527
 528
 529 int RegYUsed (struct CodeSeg* S, unsigned Index)
 530 /* Check if the value in Y is used. */
 531 {
 532     return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
 533 }
 534
 535
 536
 537
 538